This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. ABSTRACT Background: Growth failure in older children and adults with Sickle Cell Disease (SCD) is well established. Although the causes of growth delay are likely multifactorial, poor nutritional status has been most widely implicated. Zinc deficiency is thought to be pivotal. Several studies show a direct correlation in older children and adults with SCD between growth delay and alteration in body composition and zinc deficiency. However, infants with SCD have not been studied. It is unclear if the growth delays begin in infancy and whether zinc deficiency plays a role. This study will evaluate the effects of zinc status on early growth and body composition in infants with HbSS, homozygous SS disease. Hypothesis: Zinc deficiency (defined as neutrophil zinc 5th %). The mean zinc levels of the two groups will be compared. A students t test will be used to test the difference in the mean zinc levels between infants with poor growth compared to those with normal growth. I. HYPOTHESIS 1. Zinc deficiency (defined as neutrophil zinc 42 [unreadable]g/ 1010 cells) will be associated with poor growth in infants with HbSS. Specifically, we hypothesize that mean zinc levels in poorly growing infants will be at least 10% below that of normally growing infants. 2. Growth parameters (weight or length) of infants with HbSS will be less than those of unaffected healthy infants. Specifically, we hypothesize that growth parameters will be below the 5th percentile in at least 50% of infants with HbSS. II. SPECIFIC AIMS Primary Aim: To examine the association between poor growth and zinc deficiency in infants with Sickle Cell Disease, HbSS (homozygous SS disease). Secondary Aim: To establish the incidence of growth delay among infants with HbSS.